The kernel tracks the resource usage of every process, including the amount of CPU time used and the number of signals received. A resource usage object is read-only and can be queried for its individual resource values, if required.

To receive a resource object containing its resource statistics, use the method os_this_process::usage() . To obtain resource statistics for the terminated child processes of the current process, use os_this_process::usage_for_terminated_children() .

Example <ospace/unix/examples /rscusag1.cpp>


  #include <iostream>
#include <ospace/unix.h>

int
main()
  {
  os_unix_toolkit initialize;

  os_process child( "/bin/sh", "date" );

  // Usage becomes available when child terminates.
  os_this_process::wait_for_child( child );
  os_resource_usage usage = os_this_process::usage();

  cout << "os_resource_usage" << endl;
  cout
    << "  user time: " << usage.user_time() << endl
    << "  system time: " << usage.system_time() << endl
    << "  max resident set (bytes): " << usage.max_resident_set_bytes()
    << endl
    << "  average resident set (pages): "
    << usage.average_resident_set_pages() << endl
    << "  average resident set (bytes): "
    << usage.average_resident_set_bytes() << endl
    << "  page faults without I/O: " << usage.non_io_page_faults()
    << endl
    << "  page faults with I/O: " << usage.io_page_faults() << endl
    << "  number of swaps: " << usage.swaps() << endl
    << "  blocks on input: " << usage.input_blocks() << endl
    << "  blocks on output: " << usage.output_blocks() << endl
    << "  messages sent: " << usage.sent_messages() << endl
    << "  messages received: " << usage.received_messages() << endl
    << "  signals received: " << usage.received_signals() << endl
    << "  voluntary context switches: "
    << usage.voluntary_context_switches() << endl
    << "  forced context switches: " << usage.forced_context_switches()
    << endl;
  return 0;
  }

Sat Jul  8 21:01:20 CDT 1995
  user time: 0.090000 seconds
  system time: 0.110000 seconds
  max resident set (bytes): 946176
  average resident set (pages): 41
  average resident set (bytes): 167936
  page faults without I/O: 283
  page faults with I/O: 0
  number of swaps: 0
  blocks on input: 2
  blocks on output: 0
  messages sent: 0
  messages received: 0
  signals received: 0
  voluntary context switches: 2
  forced context switches: 7